Many fruits and vegetables are sold in bags with a preprinted weight. This label weight is the minimum weight of the articles. The actual weight of the articles in the bag typically exceeds the label weight to allow for shrinkage during storage and shipping of the articles. Apparatus and processes for weighing and sorting fruit or vegetable articles for grouping in bags have been described before. Such apparatus typically has a continuous conveyor carrying a plurality of pivotable cups in a loop. Each cup receives an individual article from a supply of articles. The cups pass in sequence over a weighing device to determine the weight of the article in each cup. As each article is discharged from its carrying cup into a container at a discharge zone, the weight of the articles in the container is accumulated by a controller. When the weight exceeds a predetermined value, such as the label weight for the container plus a percentage for shrinkage, the container is closed and removed from the apparatus. A new container is positioned in the discharge zone of the apparatus and filled with articles as described.
Typically, the bags of fruit or vegetables filled in this manner are sold at a price based on the label weight. The excess weight included in each container permits shrinkage and drying of the articles during storage and shipment of the containers without the total actual weight of the articles becoming less than the label weight. However, when filling bags with discrete articles, such as fruit which have nonuniform weights, simply adding the next available article to a slightly-underweight bag can yield an excess weight well over the amount required to meet the label weight of the bagged articles. This excess weight is an overage and can represent a significant cost to the packer. For instance, some such weighing and sorting apparatus fill in excess of fifty bags per minute. An overage of half a pound per container leads to an overage of twenty-five pounds per minute. For example, for bags holding five pounds label weight, the overage results in five or more "lost" bags per minute, which represents a significant loss to the packer of the articles.
U.S. Pat. No. 4,262,807 describes an apparatus and a process for weighing and sorting articles in which the selection of the last article to discharge into the container is made so as to minimize the weight overage in the container. That prior apparatus and method included parallel conveyors each of which travels in a continuous path in a vertical plane to provide an upper flight and a lower flight. A plurality of article-receiving cups is pivotably carried on the conveyor. Extending laterally from each side is a pin. The cups hang vertically during the return lower flight and are supported horizontally by the pins during travel of the cup along the upper flight. Each horizontally-disposed cup on the upper flight is loaded with an article at a loading zone, and the cups then pass in sequence through an article weighing zone containing a scale to determine the weight of the article in each cup. The conveyor then carries the cups through successive longitudinally spaced discharge zones. The discharge zones each include a support to hold a container, a device to close the container, and a discharge mechanism to direct a selected article into the container. The discharge mechanism normally allows the cups to by-pass the discharge zone. Activating the discharge mechanism at a selected discharge zone causes the cup to pivot downwardly by gravity and drop its article into the selected discharge zone.
A controller selectively actuates the discharge mechanism to discharge the selected article into a designated discharge zone, according to prescribed and different weight ranges for each discharge zone programmed into the controller. Typically, the articles will be sorted so that articles of approximately the same weight are released in the same discharge zone. As articles are selected and discharged, the controller totals the weight of articles in the container for each discharge zone. The controller scans the next series of articles to select the optimum weight article which will just top off the receptacles receiving the articles from that zone. If a weighed article is not dropped into one of the discharge zones, the article is discharged from the forward or discharge end of the sorting machine and subsequently returned by another conveyor to the loading zone for reloading a second time into another cup for reweighing and recycling.
Handling by machinery and jostling or contact of an article by other articles is an expected aspect of weighing and sorting of articles by high speed machinery, despite the bruises, blemishes or other damage the articles may receive. These kinds of damage decrease the quality of the articles and thereby decrease the value of the articles. Damaged articles may experience increased spoilage and may spoil other articles grouped in the container. Therefore, an article not discharged into a container, but rather redirected back to the loading zone, receives additional handling and bumping by machinery and by other articles not experienced by articles discharged into a container during a first selection cycle.
Thus, there exists a need in the art for a weighing and sorting apparatus and process that reduces the handling of an article loaded into a cup on a continuous conveyor for weighing, sorting and discharging into a container with a group of other articles.